this character has lots of meanings. in ur example, it means "mean..." 效用 是指 商品满足人的欲望的能力： 效用 means 商品满足人的欲望的能力. 效用 指的是 商品满足人的欲望的能力. //this phrase highlights "商品满足人的欲望的能力"

1. it same as point, like “指路"， ”指方向“>>>"指教" ，”指导“ 2. finger， ”手指“， somehow same as point with finger. Example: A: 我不知道怎么去天安门， 你能帮忙指路吗？ B：你指的是北京天安门吗？ 没问题。

In this example, 指 is "means" as a verb. Originally 指 as noun means finger (手指). When it's used as verb, it means "point to", it can be extended to "means". Actually 指 can be used in many word, like: 指导 (instruct), 指挥 (command, direct), 指引 (guide), 指向 (point to).

效用：A 是指：verbe--means 商品满足人的欲望的能力：B A means B. A：效用---->effectiveness B：商品满足人的欲望的能力 商品：product 满足：satisfy 能力：capacity 人的欲望：desire (noun) of human so, the effectiveness means the product satisfies the desire of human.

In thid sentence，“是指”means“is about” in English.but“指”has several different means in chinese. <n.>finger； e.g. 因为我爸在报纸上竖中指了! Because my dad gave the middle finger in the paper! <v.>point at；point to；bristle；indicate； e.g. 这指的是我吗？ Does this refer to me? （and off course ，the “指” in the sentence above） These two kinds of usage in common use today.